KR950007294B1 - Optical pick up apparatus of mini disk player - Google Patents

Abstract

With optical pick-up unit of Mini-disk player, the process of manufacturing is simplified and the size of the unit can be made smaller by granting the function of gating to a beam-splitter. The upper side of the beam-spliter, splitting a ray of light incident and a ray of reflection of laser beam, is coated horizontally with some mirror of total reflection, so the slit is made for transmitting a laser beam between total reflection mirrors.

Description

Optical pickup device of mini disc player

1 is a schematic configuration diagram showing an optical system of an optical pickup apparatus of a conventional mini disc player.

2 is a schematic configuration diagram showing an optical system of an optical pickup device of a mini disc player according to the present invention.

3 is an enlarged perspective view of a beam splitter applied to the optical pickup apparatus of the present invention.

4 is a side view of FIG.

5 is a side view of another embodiment of FIG.

* Explanation of symbols for main parts of the drawings

30: laser diode 32: beam splitter

34: total reflection mirror 36: slit

38: collimated lens 40: objective lens

42: optical disk 44: prism

46: concave lens 48: photo director

50: monitoring photodiode

The present invention relates to an optical pick-up device of a mini-disc player, and more particularly, a diffraction grating function is provided to a beam splitter to simplify the manufacturing process and to reduce the size of a product. An optical pickup apparatus for a mini disc player.

In general, an optical pickup device of a mini disc player irradiates a laser beam output from the laser diode 10 to a recording pit inside the optical disc 11 rotating at a constant speed, and reflects the laser beam from the recording pits. The optical system detects a beam and reproduces the recorded information. As shown in FIG. 1, the optical system includes a plurality of single laser beams output from the laser diode 10 above the laser diode 10. The diffraction grating 13 to be divided, the beam splitter 14 separating the incident light of the laser beam and the reflected light reflected from the recording feet of the optical disc 11, and the incident light passing through the beam splitter 14 are parallel to each other. A collimating lens 15 for converting light into a light beam and a laser beam converted into parallel light while passing through the collimating lens 15 are focused and recorded on the optical disc 11. While the objective lens 16 to be used is sequentially installed, the prism 17 and the concave lens 18 through which the reflected laser beam passes on the one side reflection path of the beam splitter 14 receive the reflected light and the optical disc ( A photo detector 19 for detecting the focusing and tracking states of the laser beam at the recording feet on the recording feet and reading out the recorded data is sequentially provided, and the beam splitter 14 On the other side of the C), a monitoring photo diode 20 is installed which detects a laser beam reflected from the beam splitter 14 and controls an output state of the laser diode 10.

However, in the optical pickup device of the conventional mini-disc player, a diffraction grating 13 for separating a plurality of single laser beams output from the laser diode 10 and a beam splitter for separating particle light and reflected light of the laser beam ( 14) is a structure separated from each other on the same vertical line, and thus there is a problem that it is an obstacle to miniaturization because a space for securing the path of the laser beam between the diffraction grating 13 and the beam splitter 14 is required. There was a problem that the manufacturing process is also complicated and productivity is lowered.

The present invention is to solve the above-mentioned problems, to exclude the diffraction grating in the optical pickup device of the mini-disc player, coating a plurality of total reflection mirrors on the surface of the beam splitter upper surface at regular intervals, between each total reflection mirror The optical pickup of a new type of mini-disc player that forms a slit through which the laser beam is transmitted to simplify the manufacturing process and to achieve miniaturization of the product by allowing the beam splitter to act as a diffraction grating. The purpose is to provide a device.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

As shown in FIGS. 2 to 4, the present invention excludes a diffraction grating separating a plurality of single laser beams output from the laser diode 30 in the optical system constituting the optical pickup device of the mini disc player. On the upper surface of the beam splitter 32 separating the incident light and the reflected light of the laser beam, a plurality of total reflection mirrors 34 are coated on the surface in a lateral direction, and the slits through which the laser beam passes through each of the total reflection mirrors 34 ( 36) to form a characteristic.

As another embodiment of the present invention as shown in FIG. 5, a plurality of total reflection mirrors 34 are laterally coated on the bottom surface of the beam splitter 32, and the laser beam is disposed between the total reflection mirrors 34, respectively. It has a structure in which the slit 36 is transmitted through the beam.

Such action of the present invention is as follows.

As shown in FIG. 2, a single laser beam output from the laser diode 30 is passed through the slit 36 between the total reflection mirrors 34 coated on the beam splitter 32 and into a plurality of laser beams. Separated and incident on the recording pits on the surface of the optical disc 43, the reflected light reflected from the recording pits proceeds in a path opposite to that at the time of incidence and is reflected by the total reflection mirror 34 coated on the beam splitter 32. Thereafter, the photo director 48 enters the photo director 48 through the prism 44 and the concave lens 46. The photo director 48 detects the focusing and tracking states and reads data.

On the other hand, a part of the laser beam output from the laser diode 30 is reflected toward the monitoring photodiode 52 on the rear surface of the total reflection mirror 34 coated on the beam splitter 32, and the reflected laser beam is monitored The inside of the photodiode 50 is detected to control the output state of the laser diode 30.

By applying the present invention as described above, the diffraction grating installed at the position perpendicular to the laser diode is excluded, and the installation space can be reduced by performing the function of the diffraction grating in the beam splitter, so that the product can be miniaturized. There is an effect that the manufacturing process is simplified and productivity is increased.

Claims (2)

A plurality of total reflection mirrors 34 are disposed on the surface of the beam splitter 32 that separates the incident light and the reflected light of the laser beam, excluding a diffraction grating that separates a plurality of single laser beams output from the laser diode 30. Coating in the transverse direction, the optical pickup device of the mini-disc player, characterized in that the slits 36 through which the laser beam is transmitted between each total reflection mirror (34). The miniature of claim 1, wherein the beam splitter 32 is formed by coating a plurality of front mirrors 34 on the bottom thereof in the lateral direction, and forming slits 36 between the total mirrors 34. Optical pickup device of disc player.